It is well known to have pixel representations of pictures having a better resolution than the display they were displayed on. Further it is well known to compute a representation from a picture according to a given viewers position and a given viewers direction in order to display an image on a screen which corresponds to the picture seen under the given conditions by a viewer.
It is a popular and well known method of picture representation to decompose it in a polygonal model. The surface of each polygon is filled by a so-called texture. The details in representation of a picture were growing with an increased amount of pixels representing such a texture. On the other side the time needed to calculate the representation of the texture on the screen increases with the amount of the pixel size of the picture. Especially when a real time representation of the picture is required huge calculation capacity and great memory storage were required to deal with big pixel sizes of the map, which is too expensive for ordinary computer users.
Texture mapping is a popular way of enhancing realism of three-dimensional scenes without increasing the polygonal complexity. Usually, system memory or memory dedicated as texture memory is restricted by technical and/or economical constraints. On specialized computers with high graphic abilities, the size of a single texture is limited to a resolution in the order of 1,024.times.1,024 pixels. High resolution graphics are graphics representing pictures wherein a great amount of detail has to be represented. Textures were required having a resolution of 10,000.times.10,000 pixels or more. It is impossible to use directly known and usual graphic workstations to render such textures on the terrain in reasonable time.
In the area of texture mapping, filtering techniques have been developed to adapt the pixel size used in object space to the pixel resolution of the projected pixels in the display space. A hierarchy of images is generated from the original texture using so-called MIPmap pyramid. This well known and widely used filtering method is described in L. Williams, "Pyramidal Parametrics", in Computer Graphics (SIGGRAPH 1983 proceedings), July 1983, pp. 1-11.
Further mapping textures under surfaces of computer generated objects with prefiltered MIPmap data leads by reducing the pixel size of the texture to an effect called aliasing, which aliasing gives to the viewer an impression of a blurred image on the display.